I read somewhere that fuel efficiency and emissions control has improved something like 99% since 1960. That makes sense because cars back then were horrible. They were overweight, they burned lead gasoline, and they belched a horrific amount of pollutants into the atmosphere.
Now, however, after many years of technological advances and design refinement, can gas burning cars really get anymore “earth friendly” than they are at the present time? IMHO, I really can’t see how, but that is definitely a lay person’s opinion. So, where from here? Better and better battery run cars?
They could get way better – lighter, more streamlined, more efficient. If gas was $1000 a gallon and people still drove them, just imagine the progress.
In terms of non-CO2 pollution, current cars are pretty good. But as far as CO2 g/mi, there is a lot of room for improvement. The biggest thing that could be done is to reduce the size and power of both bodies and engines. That could more than double the efficiency. But, people wouldn’t stand for it.
Hybrids help a lot, too, but are often used for increasing power instead of reducing emissions.
Gas burning cars are still pretty heavy. They could be made significantly smaller and lighter. People have an expectation of what a car is though, and don’t want something like a tiny motorcycle engine and a fragile shell for a car body. But you could easily double the gas mileage of a car, which would make it significantly greener.
As for the comparison with battery cars, this is kind of difficult to make an apples to apples comparison. Your main sources of electricity these days are fossil fuels and nuke plants. Do you count a nuke plant as “green”? Nuke plants don’t spew CO2 and other gases into the air, but they do create nuclear waste, for which there is no really good solution at the moment. And nuke plants will inevitably have nuclear accidents. How do you compare the “green” aspects of a nuke plant to a fossil fuel plant?
If you just compare gasoline engines to fossil fuel plants, pretty much no matter what you do the fossil fuel plants win. A gasoline engine is only about 30 percent(ish) efficient, meaning only 30 percent of the energy in the gasoline goes to moving the car down the road. The rest gets lost as waste heat. Power plants are more like 50 percent efficient. Plus, with a power plant, all of the gases and pollutants are in one place, which makes it easier to scrub the air as much as possible before releasing the pollutants into the atmosphere. Fossil fuel plants also concentrate the pollutants in one area. Although the pollutants do spread out from the plant, it’s not like a city full of cars where the pollutants are spread out over a huge area right from the start.
It’s very difficult to make a gasoline engine more efficient, so if you want to make a gasoline powered car more efficient, instead of focusing on the engine, you focus on the rest of the car, making it lighter, more aerodynamic, etc. And all of those things can be done to battery powered cars as well.
There is a lot of room to make both gasoline cars and battery powered cars more efficient, and therefore more green. But gasoline cars are never going to beat battery cars, even with the environmental problems of nuke plants.
The problem with green energy in general is that it’s difficult to produce in large quantities. Solar only works when the sun is out. Wind only works when the wind is blowing. There’s not much energy storage on the grid. But a lot of research is going into energy storage, and there are a lot of gains to be made there. And if you are just charging batteries, you don’t necessarily need constant energy. So there are huge improvements to be made for battery cars. Not so much for gasoline cars.
?Confused? Avg. MPG of hybrid car is about 51. Avg MPG of an ICE car is about 24. That’s more than a 100% greater fuel effeciency. How does that not have a significant impact on reducing emissions?
IANAM, but my guess is that automobile companies have gotten cars as aerodynamic and light as possible without hurting safety and comfort. As far as making the internal combustion engine more efficient, we probably can’t do that with current technology, or we can do it but it’s not cost-effective.
There something strange going on. Both with cars and air travel. Air first:
Planes have got enormously more efficient in the last 30 years. Carriers love this because [greenwashing] saving money. It’s also made air travel ridiculously cheap. So people fly more. A lot more, discounting covid, and AIUI, there hasn’t been a lot of net gain on total pollution.
As for cars, it seems as if the makers are trying to squeeze the last bit of oumph out of gas cars, before switching to electric (which they very much want*). So we see modell after model with insane amount of hp. There is e.g. the Land Rover Defender 90. It’s a small SUV, only two door, with a total length of 180". You can order it with a 5 liter V8 making 525 HP.
This is insane. Granted, it gets 19/14 mpg which I guess can be called fuel efficient, considering the power. But this is originally a farm implement, boosted to performance SUV, with off-road capabilities that no buyer ever will actually use. There is no reason for this to exist.
*This is the car makers vinyl to CD and VHS to DVD. They are going to make sooooo much money replacing 4BN petroleum guzzlers with EVs.
Because, the Hybrid could be much better.
Instead of making a car with 200HP ICE + 100HP Electric, it could be 100HP ICE and 50HP Electric. But, that would make the 0-60 times 9 seconds instead of 5 seconds.
And, people like fast cars.
This doesn’t make sense. People replace cars on a pretty regular schedule, and the automakers don’t necessarily make more when they replace them with an EV compared to an ICE.
It’s not like people have big garages full of cars that work fine and when EVs come out they’re all going to be scrapped and replaced at once. No one is “rebuying” a different medium car. They’re just buying a different technology when the old one wears out.
It’s true that tailpipe emissions of criteria pollutants (particulate matter (PM), hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx)) are a tiny fraction of what they were decades ago. As to whether gas-burning cars (without the use of any sort of electric-hybrid tech) can get any more earth-friendly, well, the answer depends on how you define the term.
Modern gasoline, spark-ignited car engines are designed to operate at a stoichiometric air/fuel ratio. That is, they mix fuel and air in just the right amounts so that all of the fuel is used up, and so is all of the oxygen. Or at least they would be used up, in theory. The reality is that combustion is never 100% complete, so you always get some HC/CO/NOx being sent down the tailpipe. That’s where the catalytic converter comes in: it’s called a “3-way cat” because the catalytic material in them fully oxidizes the HC and CO, and breaks up the NOx into harmless N2 and O2. The cat provides best conversion efficiency when the engine is operated at that stoichiometric A/F ratio, and we really care about minimizing those pollutants in the short term: HC/CO/NOx are things that make urban and suburban air bad for your health.
The bad news is that a gas engine operating at a stoichiometric A/F ratio is not as fuel-efficient as it could be. If you didn’t care about HC/CO/NOx, you could tune your engine to run lean, i.e. with more air than is needed to completely combust the fuel. The extra air mass would absorb heat from the combustion process, reducing peak in-cylinder temperatures and in turn reducing how much heat gets lost to the cylinder walls. Instead of dumping a lot of energy out through your car’s radiator, you’d send more of it down the driveline as mechanical power. Presto, less CO2 per mile. This matters in the long term for climate change, but the downside is that catalytic converter efficiency falls way off when you run lean. It’ll still clean up the HC and CO, but it won’t make much of a dent at all in tailpipe NOx emissions - and with your engine running lean, it’ll be sending a lot more NOx down the pipe to the cat in the first place.
So what’s your “earth-friendly” priority - clean air to breathe now, or more modest climate change 100+ years from now? With the current state of gasoline engine tech, you have to choose. Researchers are working to find ways to have increased efficiency and lower criteria-pollutant emissions at the same time, but it’s not easy.
Along the same lines, diesel engines of 20-25 years ago were more efficient than they are now (less CO2 per mile) because emissions regulations placed tighter limits on how much NOx and particulate matter (PM) they could emit. In addition to fitting most of these engines with exhaust aftertreatment devices that reduce NOx and also capture/oxidize PM, manufacturers typically tune these engines to inject the fuel a little later in the combustion cycle; this keeps temperatures down and reduces engine-out NOx, but it also reduces fuel efficiency. So the same dilemma applies: do you want clean air now, or a more hospitable climate 100+ years from now?
That’s all about what’s possible with the state of internal combustion engine technology. The rest is about what sacrifices consumers are willing to make (or willing to have forced on them by regulatory agencies). For example, if you don’t mind driving a very small car with a tiny engine, the Mitsubishi Mirage gets 36 city and 43 highway MPG, but it takes almost 11 seconds to get up to 60 MPH.
Most hybrids today are parallel hybrids, where the ICE is still the main engine directly powering the wheels, with the electric motor just providing some extra power.
But with a serial hybrid arrangement, where the ICE just runs a generator, and the electric motor is the thing that actually turns the wheels, the ICE can be made much more efficient, because it can be optimized to run at a constant RPM; it doesn’t need a broad power band like with a traditional ICE powered car. Nissan is developing one that they claim will attain 50% thermal efficiency; IIRC they best we’ve been able to get with a traditional car is around 30%.
Gasoline engines are as about as efficient as they can get per gallon of gas under ideal conditions. The use of gasoline engines in hybrids and CVTs get closer to ideal conditions for the engines but there is so much more to a car than that. The ideal conditions would ignore pollution so the engines could be slightly more efficient. The engine would also sit on a stand and not go anywhere eliminating friction losses throughout the drive train. It also wouldn’t have to propel the additional weight of a car body, suspension, fuel tank, spare, passengers, and one of those pine tree air fresheners. So a slightly more efficient gasoline engine will not be much of an improvement compared to cutting the weight of the car.
Of course not.
By '85 I had about 500 vinyl albums. I bought new music that was released on CD and gradually started replacing the vinyl when I could afford. About ten years later, the vinyl went into the basement.
I didn’t have nearly as many movies on VHS, but the trajectory was basically the same.
Now, if you were alive then, you probably remember CDs being quite a lot more expensive than vinyl, the same went for VHS/DVD.
A music album isn’t a car and people won’t scrap their ICEs and buy an EV on a whim. But if [generic] you live in a somewhat affluent country that is not the US, you must’ve noticed the speed with which ICEs are being replaced. What happens to the old cars? Shipped to developing countries.
In Sweden, where I live, EV and PHEV accounted for 55% of new sales in September. Light trucks for commercial use are lagging a bit behind with 17%. The supply chain issue is still ongoing. A friend just ordered a new ID4. Delivery is expected early Q2.
So yes, there’s a huge paradigm shift, and as with CDs and DVDs, the price for a shiny new toy is often twice as high.
I’m not sure I follow your argument here, but the market for cars and for recorded media are very dissimilar.
Cars wear out over time and need to be replaced.
People generally have a pretty inelastic need for a car.
Cars have high input costs per unit.
Recorded media generally does not wear out given normal use.
Recorded media is a luxury and convenience item.
Recorded media has very low input costs per unit.
Every time someone rebuys a piece of recorded media that they already owned in an earlier format, it’s almost pure profit. Format switches drive lots of extra profit because of this. But every time someone buys an electric vehicle to replace a gas vehicle… it’s generally because the gas vehicle is mostly used up and they were going to buy a new vehicle anyway. And the profit margin on electric vehicles is lower than the profit margin for ICE vehicles.
EV are more expensive to purchase, but most of that added cost is due to more expensive inputs (batteries!) due to capitalizing refueling costs.
The switch from ICE to EVs has not as yet provided the sorts of profit boosting that the CD or DVD did, and there’s really very little reason to expect them to because the markets are not remotely analogous.
The way that is worded, you are right to be confused. The vehicle manufacturers are often not reducing their engines to fully account for motor power, resulting in greater peak power in hybrid models. Granted, the HEVs are heavier, but you’ll still often see faster 0-60 times.
That said, the overall hybrid package with regenerative braking and avoiding the most inefficient engine use still comes out ahead. Just make sure you’re comparing like models, as it’s often the ones that are already relatively efficient that are offered as HEVs. I’m seeing more along the lines of a 25-30% reduction in fuel use per distance from my random but low-N sampling.
I large part of that is planes have gotten large. And there appears to be greater efficiencies in greater sized aircraft. That works somewhat for road vehicles too, as a full bus is typically more eco friendly than if all those people in the full bus drove ICE cars instead.
Not really. In fact, large aircraft can be less efficient per passenger mile because they generally have more engines for overwater flight, and because they are more likely to fly at a lower passenger fill rate. The most efficient passenger planes are turboprops, and they aren’t big.
The reason airplanes are more efficient now is partly about the switch from turbojet engines to high-bypass turbofans. Also, airlines now put fewer first class seats in and reduce legroom to pack in more seats. Passengers hate it, but it’s more fuel efficient. New airplanes are somewhat lighter than old ones due to composites and newer materials.
Digital fly-by-wire saves quite a bit of weight as well, and allows active computer control, allowing the plane to have less dynamic stability which translates into more fuel efficiency because of lowered induced drag. Computer aided design and advanced aerodynamics (winglets, vortex generators, etc) have eaked out another 20% or so in fuel efficiency in the latest jets.
But a huge factor is simply efficient airline operations. All the stuff passengers hate such as over-selling seats ensures that the planes fly closer to capacity, and there is nothing less efficient than flying an empty seat.
It’s true that a fully loaded bus will be more efficient per passenger mile than a car, but buses rarely travel fully loaded. Buses can actually be worse than cars, because the buses have to run sometimes at very low passenger rates. As a system, city buses are not great for energy efficiency, but it will vary wildly by route. If buses only ran on dense routes during periods when they are likely to be full, they would be maybe three or four times as efficient as modern cars. Run a bus empty at midnight, and you are sucking down fuel for no reason.
Typical bus systems that have to accomodate many routes and run at off-peak times are not very efficient.
That’s a misleading stat, because the class of vehicles that are hybrid don’t include the gas guzzlers that make ICE numbers worse, and because the hybrid fleet is newer and fuel efficiency has gone up for all vehicles over time.
The best way to compare them is to find car models that offer both hybrid and conventional powertrains of similar capcity and compare their fuel efficiency. For example, the new Ford Escape hybrid gets 41 mpg combined. The equivalent gas Escape gets 30. That’s roughly a ~27% improvement. Nowhere near 100%.
It’s certainly true that the original stat is misleading, but you’re using percentages in a different way. 41 mpg is a 37% improvement over 30 mpg given how Omar_Little calculated it. Or, the original improvement was 53% compared to your number of 27%, if you want to use the reciprocals (i.e., consumption, not efficiency).